So you think your sibling got all the breaks? Try topping the tale of Martha Clooney in Declan Hassett’s play “Sisters,” a diptych of despair set in rural Ireland. The production, at the 59E59 Theaters, occasions the welcome return to the New York stage of Anna Manahan, the Irish actress who won a Tony in 1998 playing the ferociously needy mother in Martin McDonagh’s “Beauty Queen of Leenane.” A bit less welcome is Mr. Hassett’s relentlessly downbeat play itself.

To hear the 70-year-old Martha tell it, while she toiled and trudged in the dark, her sister Mary spent her life gamboling in the purest sunshine. Mother’s love was all Mary’s. Only Mary got to escape the constrictions of Irish village life, pursuing a glamorous career as a teacher in Dublin. When it came to men, Mary had it all over poor Martha, too. She’d come home to share stories of romantic adventure with their mother, and on the one occasion that a handsome lad showed a little interest in Martha, Mary swooped in and cut him off, dragging Martha back home to the cage of her spinsterhood.

This history of cruel fate and sororal perfidy forms the first of the two monologues performed by Ms. Manahan that compose “Sisters.” As she awaits Mary’s arrival at the home they share, Martha lays her lifetime of grievances at our feet, unquietly imploring our pity. It’s Martha’s birthday, but no other guests are expected. Martha was never one to mingle much in society, unlike that gadabout Mary.

Martha expended her whole life’s affection on her father, who loved her as her mother never did and died too soon. In the blinding heat of that love, Martha appears to have missed a clue to the otherwise chilly atmosphere of the sisters’ childhood. She didn’t quite catch on that those beloved visits to the pub she shared with Dad were not just father-daughter field trips. The lass behind the bar was an attraction, too.

Ms. Manahan garnishes Martha’s litany of complaint with a few delicious cackles, suggesting the surreptitious pleasure Martha has taken in the occasional small victory over her mother’s indifference or her sister’s presumption. But there’s no escape from the suffocating atmosphere of her bitterness.

Aggrieved or resentful characters can certainly make lively company onstage, as indeed the warring mother and daughter did in “Beauty Queen,” but the monologue format does no favors for poor Martha. Her subjects are few — boundless love of dad, boundless hate of mother, boundless envy of sis — and by the time she’s finished her sorry spiel, she has long since exhausted them. And us.

Beckoning from the far side of intermission, however, is the promise of hearing Mary’s side of the story, which surely will bring at least a few warming rays of happiness. Or the captivating spectacle of wickedness triumphant, at least.

But the mechanical irony driving the play soon clicks into place. As Mary relates, in more cultivated tones, her own uneventful history, it becomes clear that she has also lived a life of emotional deprivation and loneliness. Envy blinded Martha to the truth of her sister’s life, and to the possibility of consolation in shared sorrow. Inheriting a legacy of distrust from their parents, they have served separate sentences of solitary confinement, side by side in the same house.

Mr. Hassett’s writing is skillful and fluid, but it never approaches the emotional depth or lyricism of the work of Brian Friel or Conor McPherson, to name two Irish writers capable of reaping rich theatrical rewards from the tricky monologue format. Striving a little strenuously for tragic dimensions, “Sisters” verges on the morbid in both its mood and its details. It seems a cruel contrivance to have both sisters blighted by the same man, for instance. Equally artificial, given the characters of Mary and Martha as they have been presented to us, is the revelation of a violent denouement to the sisters’ quiet tug of war.

Under the restrained direction of Michael Scott, Ms. Manahan does much to gloss over these flaws by sustaining a note of simple human truth, with equal care taken in the portrayals of Martha’s coiled bitterness and Mary’s gentle resignation. The performances are a fine matched set, as it turns out Mr. Hassett’s sisters in misery are, too.